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ADS5409 Data valid window

Intellectual 350 points

Replies: 6

Views: 1692

Hello.

From Datashet on ADS5409 , Setup and Hold time, is  230 ps. This means that valid data window is 460 ps? 

6 Replies

  • Guru 68690 points

    Eugene,

    Yes.

    Regards,

    Jim

  • In reply to jim s:

    Thank you, Jim!
    This window mesured for minimum LVDS current strength? If it is true - what is the length of the window for 3.5 mA current?
    Also interesting - this window for logic switching('1' / '0') or for specifying pattern?
    Best regards,
    Eugene Volkov.
  • Guru 68690 points

    In reply to Eugene Volkov:

    Eugene,

    The numbers specified in the data sheet are with the LVDS strength at the default value, which is 3.5mA. I am looking into your other question.

    Regards,

    Jim

  • Guru 68690 points

    In reply to Eugene Volkov:

    Eugene,

    Minimum setup and hold time spec will cover all possible cases of switching (analog input or ramp or all outputs toggling).

    Regards,

    Jim

  • In reply to jim s:

    Hi!
    I have question about data valid window too. I understand that it is 460ps for 900MSPS when decimation filter is disabled. Is it the same when decimation filter is enabled?
    Best regards,
    Kuba
  • In reply to Jakub Niemczyk:

    Hi,

    when the decimation filter is enabled, the data rate of the sample bus will be half, so the clock period of the sample clock will be longer.  The data valid window will be longer as well, but I do not see characterization data for how much longer the data valid window will be.  The extra time of the longer clock period will add to the data valid window, but I do not know if all of the longer clock period will add to setup, or add to hold, or add half of that extra time to each of setup and hold.  If possible, I think it safest to continue to use the specified 230ps of guaranteed setup time and 230ps of guaranteed hold time. 

    Regards,

    Richard P.

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